The small paired structures at the base of the penis that secrete a thick is called

These are Cowpers's gland. (Bulbo Urethral Gland)

Explanation:

These are small pea-sized glands at the base of the penis which connect each with the urethra through a short duct. It is thorough this ducts that secretion from each gland gets to the urethra.

They secretes thick alkaline fluids for lubrication of urethral and tip of the penis, for expulsion of left over urine, dead cells, mucous from the urethra for clean sperm passage.

The serrations also neutralise the acidity of the urethral